Added test class and fixed issue.

Author: tastybento

src/main/java/world/bentobox/challenges/database/object/requirements/CheckPapi.java

@@ -183,6 +183,10 @@ public boolean parseCondition() {
             String leftOperand = leftSB.toString().trim();
             String rightOperand = rightSB.toString().trim();
 
+            if (rightOperand.isEmpty()) {
+                return false;
+            }
+
             // Evaluate the condition:
             // If both operands can be parsed as numbers, use numeric comparison;
             // otherwise, perform string comparison.

src/test/java/world/bentobox/challenges/database/object/requirements/CheckPapiTest.java

@@ -0,0 +1,102 @@
+package world.bentobox.challenges.database.object.requirements;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.when;
+
+import org.bukkit.entity.Player;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.stubbing.Answer;
+import org.powermock.api.mockito.PowerMockito;
+import org.powermock.core.classloader.annotations.PrepareForTest;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+import me.clip.placeholderapi.PlaceholderAPI;
+
+@RunWith(PowerMockRunner.class)
+@PrepareForTest(PlaceholderAPI.class)
+public class CheckPapiTest {
+
+    @Mock
+    private Player player;
+
+    @Before
+    public void setUp() {
+        PowerMockito.mockStatic(PlaceholderAPI.class, Mockito.RETURNS_MOCKS);
+        // Return back the input string
+        when(PlaceholderAPI.setPlaceholders(eq(player), anyString()))
+                .thenAnswer((Answer<String>) invocation -> invocation.getArgument(1, String.class));
+    }
+
+    @Test
+    public void testNumericEquality() {
+        // Using numeric equality comparisons.
+        assertTrue(CheckPapi.evaluate(player, "40 == 40"));
+        assertFalse(CheckPapi.evaluate(player, "40 == 50"));
+        assertTrue(CheckPapi.evaluate(player, "100 = 100"));
+        assertFalse(CheckPapi.evaluate(player, "100 = 101"));
+    }
+
+    @Test
+    public void testNumericComparison() {
+        assertTrue(CheckPapi.evaluate(player, "40 > 20"));
+        assertFalse(CheckPapi.evaluate(player, "20 > 40"));
+        assertTrue(CheckPapi.evaluate(player, "20 < 40"));
+        assertFalse(CheckPapi.evaluate(player, "40 < 20"));
+        assertTrue(CheckPapi.evaluate(player, "30 <= 30"));
+        assertFalse(CheckPapi.evaluate(player, "31 <= 30"));
+        assertTrue(CheckPapi.evaluate(player, "30 >= 30"));
+        assertFalse(CheckPapi.evaluate(player, "29 >= 30"));
+        // Extra tokens beyond a valid expression.
+        assertTrue(CheckPapi.evaluate(player, "40 > 20 extra"));
+
+    }
+
+    @Test
+    public void testStringEquality() {
+        // String comparisons with multi-word operands.
+        assertTrue(CheckPapi.evaluate(player, "john smith == john smith"));
+        assertFalse(CheckPapi.evaluate(player, "john smith == jane doe"));
+        // Using inequality operators.
+        assertTrue(CheckPapi.evaluate(player, "john smith <> jane doe"));
+        assertFalse(CheckPapi.evaluate(player, "john smith <> john smith"));
+    }
+
+    @Test
+    public void testStringLexicographicalComparison() {
+        // Lexicographical comparison using string compareTo semantics.
+        assertTrue(CheckPapi.evaluate(player, "apple < banana"));
+        assertTrue(CheckPapi.evaluate(player, "banana > apple"));
+        assertTrue(CheckPapi.evaluate(player, "cat >= cat"));
+        assertTrue(CheckPapi.evaluate(player, "cat <= cat"));
+    }
+
+    @Test
+    public void testMultipleConditionsAndOr() {
+        // AND has higher precedence than OR.
+        // "john smith == john smith AND 40 > 20" should be true.
+        assertTrue(CheckPapi.evaluate(player, "john smith == john smith AND 40 > 20"));
+        // "john smith == jane doe OR 40 > 20" should be true because second condition is true.
+        assertTrue(CheckPapi.evaluate(player, "john smith == jane doe OR 40 > 20"));
+        // "john smith == jane doe AND 40 > 20" should be false because first condition fails.
+        assertFalse(CheckPapi.evaluate(player, "john smith == jane doe AND 40 > 20"));
+        // Mixed AND and OR: AND is evaluated first.
+        // Equivalent to: (john smith == jane doe) OR ((40 > 20) AND (10 < 20))
+        assertTrue(CheckPapi.evaluate(player, "john smith == jane doe OR 40 > 20 AND 10 < 20"));
+    }
+
+    @Test
+    public void testInvalidFormula() {
+        // Missing operator between operands.
+        assertFalse(CheckPapi.evaluate(player, "40 40"));
+        // Incomplete condition.
+        assertFalse(CheckPapi.evaluate(player, "40 >"));
+    }
+
+}